Device, special paper, and method for producing shaped articles

ABSTRACT

The invention relates to a device, a special paper and a method for producing three-dimensional objects.

CLAIM OF PRIORITY

This present application is a divisional of U.S. patent application Ser.No. 15/105,993 filed on Jun. 17, 2016, which is a national phase filingunder 35 USC § 371 from PCT Application serial number PCT/EP2014/003378filed on Dec. 16, 2014, and claims priority therefrom. This applicationfurther claims priority from European Patent Application EP 13005959.5filed on Dec. 20, 2013. The U.S. patent application Ser. No. 15/105,993,PCT Application Number PCT/EP2014/003378 and European Patent ApplicationNumber EP 13005959.5 are each incorporated herein in their entireties byreference.

The invention relates to a device, a special paper and a method forproducing three-dimensional objects.

A method for producing three-dimensional objects from computer data isdescribed in the European patent specification EP 0 431 924 B1. In thismethod, a particulate material is applied in a thin layer to a platform,and a binder material is selectively printed onto the particulatematerial, using a print head. The particle area onto which the binder isprinted sticks together and solidifies under the influence of the binderand, if necessary, an additional hardener. The platform is then loweredby a distance of one layer thickness into a build cylinder and providedwith a new layer of particulate material, which is also printed asdescribed above. These steps are repeated until a certain, desiredheight of the object is reached. A three-dimensional object is therebyproduced from the printed and solidified areas.

After it is completed, this object produced from solidified particulatematerial is embedded in loose particulate material and is subsequentlyremoved therefrom. This is done, for example, using an extractor. Thisleaves the desired objects, from which powder deposits are removed, forexample by manual brushing.

Of all the layering techniques, 3D printing based on powdered materialsand the supply of liquid binder is the fastest method.

This method may be used to process different particulate materials,including natural biological raw materials, polymers, metals, ceramicsand sands (not an exhaustive list).

In the powder bed-based system, a complex powder handling ischaracteristic, which makes any use outside of an industrial environmentmore difficult.

Additive manufacturing methods for producing three-dimensional objectaccording to a data record are known from the literature, some of whichwork with layered source materials such as paper and thus circumvent thepowder handling.

The layer data that represents a section of the model at the particularheight may be used, for example, in a method for the purpose of cuttinga special paper along the desired layer contour, using a laser or ablade guided on a plotter mechanism. The paper may be coated on oneside, for example, with an adhesive. Another layer of paper is thenplaced on the cut paper layer and glued to the preceding layer. Anothercutting operation now takes place, whereby only the current paper layershould be separated on the basis of the current contour data. Theoperations of applying paper and cutting are repeated until the desiredcomponent is completely contained in the paper stack. Lastly, the papersurrounding the contour must be separated from the component. This maybe made easier if additional auxiliary cutting paths are introduced intothe paper stack.

A procedure of this type is described, e.g., in U.S. Pat. No. 5,730,817and is generally known under the term, Laminated Object Manufacturing,or LOM for short.

Another advantage of the technology lies in the use of paper orpaper-like materials, which are cost-effectively available and may bepurchased in a high standard of quality. In this case, the paper is fedto the device in the form of a roll.

In another specific embodiment by the MCor company, commercial paper inthe form of sheets is used in the A4 size typical for printers. Thesheet of paper is again cut with a blade. With the aid of a specialapparatus, adhesive is applied to the paper only in the locations wherethe later object will be produced. This has the advantage that thesurrounding paper layers may be very easily detached from the actualmodel. A new sheet of paper is subsequently placed on the stack, recutand glued. The operation is repeated until the desired paper is presentin the paper stack. Once again, the surrounding paper must then beremoved to obtain the component.

The disadvantage of the aforementioned systems is that expensive specialmachines are needed for producing the 3D object, which the customer mustfirst acquire and install.

The investment in the technology is generally too high, in particular,for customers who have only an occasional need for printed 3D objects.

One object of the application was therefore to provide a method whichmakes it possible to create three-dimensional objects according to a CADdata record without high investment costs.

Another object of the application was to provide materials which may beused to produce three-dimensional objects easily and cost-effectively,using common printers.

A further object of the application was to provide methods and, ifnecessary, materials which at least partially mitigate the disadvantagesof the prior art or avoid them altogether.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, the invention relates to a device for producing 3Dobjects.

In another aspect, the invention relates to a special paper which issuitable for producing 3D objects.

In another aspect, the invention relates to a method for producing 3Dobjects.

In another aspect, the invention relates to a method for producing 3Dobjects for use as casting molds, which are preferably subjected toadditional method steps following a first method step.

DETAILED DESCRIPTION OF THE INVENTION

A number of terms in the invention are explained in greater detailbelow.

Within the meaning of the invention, “3D printing method” relates to allmethods known from the prior art which facilitate the construction ofcomponents in three-dimensional molds and are compatible with thedescribed method components and devices.

“Selective binder application” or “selective binder system application”within the meaning of the invention may take place using any currentlyavailable printing technology. This includes ink-jet printers, laserprinters and dot matrix printers.

“Molded body” or “component” or “object” within the meaning of theinvention are all three-dimensional objects that are produced with theaid of the method according to the invention and/or the device accordingto the invention and which have a nondeformability.

A printing machine, which has a similar or identical design to a paperprinting machine, is used as the “device” for carrying out the methodaccording to the invention, also generally referred to as a “printer.”It may be designed as a sheet or roll machine. As a result, it containspaper feeding, separating, guiding and centering apparatuses, typicallya printing unit, a fixing unit, a product storage apparatus and othercomponents known to those skilled in the art, which therefore do notneed to be discussed in greater detail here.

According to the invention, “paper” or “special paper” is understood tobe a flat, smooth material layer of a defined thickness. The thicknessis much less than the other two dimensions. However, “paper” is notstrictly understood to be paper in the classic sense but ratherfilm-like or sheet-like materials that are structured in such a way thatthey have the necessary properties for the method described. Inparticular, they may be selectively bound, and a molded part may beremoved from the unbound special paper. In particular, the materialsdescribed below may be used for this special paper.

A “sheet” is a piece of paper which has two dimensions of approximatelythe same size. The factor between the dimensions is typically not morethan three.

A “roll” is also a piece of paper, the dimensions deviating greatly fromeach other. Factors of up to several thousand are not atypical.

“Binding” is the step according to the method, in which a block isformed from the loose paper stack. At least the printed or the unprintedareas are bound.

“Remove” or “separate from unbound special paper” means that thecomponent is released from the paper stack or the roll. Baths fordissolving unwanted material may be used, as may melting processes orburn-off processes that pulverize the paper.

“Finishing” is an intermediate step in the method, which makes itpossible to intensify the effect of the material or the informationapplied by the printing process for subsequent processes such as bindingor removal.

Within the meaning of the invention, “positive printing” is understoodto be the fact that an object is produced directly, which forms theessentially desired shape. This object may still be finished orsubjected to additional method steps.

“Negative printing” within the meaning of the invention is understood tobe that a 3D body is produced, which may be used as a casting moldeither directly or after additional treatment steps for the purpose ofproducing the ultimately desired object.

The invention, along with its preferred specific embodiments, isdescribed in greater detail below.

One core of the invention is the finding that nearly every consumer inan industrial country today owns a 2D printer. According to theinvention, this printer is used to produce layers with the aid ofspecial paper. The 3D body is then produced from the layers in one ormultiple finishing treatment steps. Another step then deals withreleasing the object from the paper stack. Both steps following printingand stacking should be able to be carried out using simple means, atbest those available in the home.

In other embodiments, the advantages of this method are transferred tonew types of devices, since this offers significant advantages over theprior art, not only in the area of low investments.

In one aspect, the invention relates to a device that is suitable forproducing a three-dimensional body from individual layers, including:

a. an apparatus for guiding and positioning special paper;

b. a printing device for printing special paper

c. a finishing treatment and/or calibration unit, a sensor systemobtaining, during production, position information in a series ofspecial papers in a stack or a roll, which may be used to correct theprinted images and the position of these images.

All known and suitable printer units may be used in this device, thedevice preferably being or having an ink-jet print unit, a laser printunit and/or a dot matrix print unit.

The device may furthermore include a temperature control unit.

In another aspect, the invention relates to a special paper that issuitable for producing a three-dimensional body from individual layers.The special paper preferably has the following properties:

-   -   a. activatable tendency to bind with an adjacent layer of a        special paper;    -   b. variable tendency to be dissolved by printing with a medium;    -   c. capacity of the special papers to bind to each other, due to        the activation in the areas defined by printing;    -   d. solubility of the unbound special paper due to the action of        a suitable solvent, heat and/or mechanical energy

The special paper may contain all materials that may be glued or boundtogether, or it may be made therefrom; the basic substance of thespecial paper is preferably made of cellulose fibers, or it is selectedfrom the materials of plastic, naturally occurring substance, metal,stone, mineral or ceramic, or it is a combination of these substances.

It is advantageous from an environmental standpoint if the componentscontained in the special paper are essentially non-toxic.

As described, printing preferably takes place in multiple layers, i.e.on a series of sheets of special paper, and the sheets obtained in thismanner are then bound together in a selected sequence in another stepfor the purpose of producing the three-dimensional object. The specialpaper has a binding capacity which may take place due to a fluid or apowder.

The binding capacity preferably takes place by adding a substance orchanging a property of the special paper, preferably the activationtakes place by transferring fluid or powder on the ink ribbon of a dotmatrix printer, an ink-jet printer or by the fixed powder of a laserprinter or copier. The binding capacity more preferably takes place dueto a variable microwave selectability in the special paper, or thebinding capacity takes place due to the presence or lack of a diffusiblemedium. The binding capacity more preferably takes place via thediffusion of a temperature-activatable substance.

The special paper may be provided in all suitable forms, preferably inthe form of sheets or rolls.

In another aspect, the invention relates to a method for producing athree-dimensional body, including the steps:

-   -   a. printing special paper as described above;    -   b. repeating the printing process until all sectional drawings        of a three-dimensional body are present on the special paper in        a given layer thickness of the special paper;    -   c. organizing all printed special papers obtained in step b.)        into a suitable arrangement; d. binding the special papers        arranged in this manner;    -   e. removing the obtained three-dimensional body from unbound        special paper.

In the method according to the invention, the special paper ispreferably used in individual sheets, unseparated or perforated paperrolls.

Printing takes place with the aid of suitable printing means, preferablyan ink-jet, dot matrix or laser printer.

In one preferred step, a water-containing substance is applied to thespecial paper, preferably by an ink-jet printer, a thermoplastic isapplied to the special paper, preferably by a laser printer, or a highlyviscous adhesive is applied to the paper, preferably by the ribbon of adot matrix printer, and the selected areas are thus preferably bound.

The binding of the material of the selected areas may preferably betriggered by thermal energy and/or by pressure. The binding is morepreferably triggered by another substance.

The three-dimensional body obtained in this manner may preferably beremoved from the unbound special paper by a dissolution process in asolvent, by a thermal process or mechanically.

Following the method according to the invention, the three-dimensionalmolded body may preferably be subjected to additional processing steps,preferably a saturation or a perfusion of the three-dimensional moldedbody and/or an application or introduction of a substance for hardeningthe three-dimensional molded body.

The special paper according to the invention may furthermore be used inall methods which are suitable for producing three-dimensional objects.

One aspect of the invention is furthermore a three-dimensional objectproduced with the aid of one of the methods described above.

Preferred aspects of the invention are described in greater detailbelow.

In one aspect, the invention relates to an application in the home area.This refers to users who only rarely require a 3D object and own anormal 2D printer.

According to the invention, the user is to insert and print a specialpaper (100) into the normal printer. The particular printouts are thesectional drawings of the 3D object. The layer thickness, and thus thecutting position in the data record, are defined by the layers alreadyprinted and the sheet thickness. For example, a laser printer, anink-jet printer or a dot matrix printer is used as the printer (FIG. 2).Different materials may be applied thereby.

For example, the printed material may be largely water which is usedsolely as an information carrier. It may itself change a property inspecial paper (100), or it may be used after a finishing process (FIG.3). A composition of this type may be found in the inks of an officeink-jet printer. The water may also contain a soluble plastic, which iscross-linked in a subsequent oven process and thus results in thedesired body, the special paper immobilizing the print medium in thiscase.

Alternatively, an image (203) made of a polymer is melted with the paperusing a laser printer.

A dot-matrix printer usually applies a highly viscous ink. It may againbe used in a finishing process.

Sheet stack (102) from the printer is subsequently sorted thereon andprecisely stacked. The user then places the stack, e.g., in the homeoven, for the purpose of binding the individual layers. Heat (103)melts, for example, part of the printed image and diffuses into one orboth adjacent sheets, preferably the top sheet.

Different mechanisms may be activated. On the one hand, the moltenmaterial is distributed in all spatial directions (402). On the otherhand, additional constraining forces become active, such as gravity oran externally applied pressure (403, 404).

It is likewise possible to place the sheet stack in a home microwave.This is suitable, in particular in connection with the use of an ink-jetprinter. The printed water may be prevented from evaporating bycomponents, such as solid thickeners (e.g., xanthan gum, gelatin,polyvinyl alcohol, polyethylene glycoles, molar mass >600 g/mol) and/orliquid thickeners (e.g., propylene glycol, glycerin, polyethyleneglycol, molar mass <600 g/mol) in special paper (100). In the microwave,energy is absorbed in the printed locations in a targeted manner andheat is effectively produced, due to the high absorption of themicrowave radiation of the water. The high heat development, in turn,may be used to locally melt a component provided in special paper (100)and thus bind sheet stack (102).

In an alternative specific embodiment, only the unprinted areas melt,since the evaporation cold results in the fact that the temperature inthe printed locations is not high enough to melt the component (e.g.,plastic) contained on the special paper, e.g. due to the lack of ahumectant and/or more volatile constituents in the printing medium.

Thus solidified, sheet stack (102, 401) is placed in a solvent, e.g., awater bath (501). The unprinted paper dissolves, and desired molded body(104) is released.

In an alternative specific embodiment, the user removes the sheet stackfrom the printer and sorts and stacks it. The user now places the stackinto a liquid medium, e.g. an artificial resin, for binding theindividual layers. The liquid then penetrates only the printed areas,because the special paper has developed a special absorption capacity,for example due to the dissolution of a protective layer with respect tothe resin and the ability to mix with the print medium. In another case,the liquid penetrates only the unprinted areas, since the printed areashave been sealed against the introduction of liquid, and the resin isunable to mix with the print medium. The liquid now hardens, e.g. due tochemical reaction, after a certain waiting time or by the action ofenergy in the form of heat or radiation, and binds the desired moldedbody. At the end of the reaction, the special paper surrounding themolded body is dissolved, e.g. in a solvent.

One essential prerequisite for this method is the use of non-toxic andeasy-to-handle special paper and the ability to use preferablycommercial print media. No toxic substances should be released eitherduring handling or during binding. Likewise, the dissolution processshould preferably not cause waste water pollution.

A method is thus created, which makes it possible to carry outproduction at home in the case of low demand for 3D objects. Only astack (102) of special paper (100) is needed for this purpose. Theremaining requirements already exist in most homes.

A key component in this method is special paper (100). It must beactivatable with the aid of commercial printers without damaging them.The activation must result in a binding of the individual paper sheets,and the mold must be removed after the process.

The activation may take place using a commercial laser printer (FIG. 2a), as briefly discussed above. During the printing process, a layer(203) of a water-insoluble, thermoplastic is applied to the paper andfixed by melting.

To be able to carry out the other steps, paper (100) may have awater-soluble design. Layers (203) applied by the printing processpenetrate the paper, due to the oven process, and change the solubility.After dipping the sheet stack into a water bath (501), molded part (104)is available.

Interestingly, a full color molded part may also be obtained by means ofthe method, if the color information for the printout is contained inthe molded part. For this purpose, the data, including the layer-precisecolor information, is printed onto the special paper with the aid of anink-jet printer or laser printer and further processed as describedabove.

In a second aspect, the method according to the invention also offersadvantages for industrial applications. The investments here aresecondary. However, new properties may be achieved by piling papers intoa stack, binding and removing them.

In particular, the main point here is the achievable productioncapacity. For example, different sheets may be printed simultaneously.The sheets are subsequently placed in the layer sequence by forming astack (102).

It would likewise be possible to print on a paper roll (600). The rollacts as a paper stack during removal. The data must be adapted to thecircumstances. Once again, different parallelizations are possible here.For example, multiple rolls may be printed and wound together.

Another advantage of the use of special paper (100) lies in the specialproperties that may be achieved within the layer. A wide range of basematerials may be used. For example, a higher density may be producedwithin a layer, compared to powder-based 3D printing. This constitutes asignificant advantage, e.g., in the case of sintering materials.

This system may also be used to process solidifying materials that tendto shrink. Thus, thermal expansions are not active if the special paperis adequately dense.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1: shows a schematic representation of the method according to theinvention

FIG. 2: shows a schematic representation of different printing methods;

FIG. 3: shows a diagram of finishing methods;

FIG. 4: shows the binding of the layers by means of diffusion, gravityor pressure;

FIG. 5: shows different processes for removing the molded part

FIG. 6: shows a device according to the invention for producing 3Dmolded bodies with the aid of paper rolls.

Additional details, examples of preferred specific embodiments andadvantages of the invention are discussed below.

EXEMPLARY EMBODIMENTS Exemplary Embodiment 1 (Special Paper-LaserPrinter-Home Oven

In this embodiment of the invention, the focus is on home application.The embodiment facilitates the following scenario. A user isparticularly interested in a 3D object on the Internet. He buys thespecial paper that is compatible with his 2D printer. Special softwarethen allows him to convert a 3D format into individual 2D images. Theoperation is also accompanied by the program, and software assistantsare provided that control the sheet sequence. The user can now print outhis stack. After careful layering, the entire stack is placed in theoven. After a cooling phase, the user flushes his component out of thestack.

This technology enables the user to produce a 3D component at home inless than 1 day. He does not have to make any investment or possess anyspecial technical skills.

The paper composition is crucial to the process steps. In thisapplication example, cellulose-based paper is used. The fibers are shortand have a length that is far less than the sheet thickness. The sheetthickness is 80 μm, and the fibers are therefore 20 to 30 μm in length.

The grammage of the paper must be far less than 60 g/m². It is thus avery loose and lightweight paper.

The paper is bound by means of a water-soluble substance. In thisexample, the polymer polyvinyl alcohol (PVA) is used. The latter may beeasily removed in the flushing process. Warm water increases the speed.If residues of PVA enter the sewage system, this does not pose anenvironmental hazard, since this plastic is biodegradable.

The polymer must be selected in terms of its melting point or glasstransition in such a way that it survives the fixing process duringlaser printing and does not melt. Otherwise, the printout would bedamaged.

This special paper (100) is subsequently printed according to layer data(101). The printing program ensures a numbering of sheets (100) and thehighest possible toner application in each case. Individual sheets (100)are compiled into a stack (102, 400).

Toner based on polymethyl methacrylate (PMMA) is generally used in laserprinters. This toner, which is made of micro-balls, is stuck to thepaper in a layer (203) according to the data and subsequently meltedwith the paper due to high heat.

A paper printed in this manner demonstrates the desired hydrophobicproperty when placed in water. The image remains in the form of a thinfilm. The rest of the paper dissolves when gently stirred.

This stack (400) is then subjected to finishing treatment by heat (103)in the oven. Since paper (100) is generally a poor heat conductor, theoperation must last several hours, for example in the case of a 10-cmstack made of DIN A4 papers (400). The glass transition temperature ofPMMA must again be exceeded to bind the paper. The glass transitiontemperature of the PVA should advantageously not be exceeded so thatentire stack (401) is not compressed and thus harder to dissolve lateron. The oven must therefore be expediently set to approximately 100° C.

Paper stack (401) is then removed from the oven. To avoid internaldistortion of the component because the thermoplastic is still soft,stack (401) must be cooled after the oven treatment. Once again, acertain amount of time is needed in this case, due to the heatconductivity. Stack (401) described above, which is 10 cm high and hasthe dimensions of a DIN A4 paper, should be age-hardened at roomtemperature for one hour.

To dissolve (FIG. 5) the unprinted paper, stack (401) is placed in awater bath (501). This may be a tub or a sink. Warm water acceleratesthe operation. Additional rubbing by hand or with a brush detachesadhering paper faster (500). The water should not be too hot to preventthe component from distorting, and to avoid scalding the user. If thebinding of the layers is insufficient, the individual layers willseparate from each other.

According to the invention, it is highly preferred that the basicsubstance of paper (100) is absolutely non-toxic and does not harm theenvironment. Dissolved material (502) may now be roughly separated fromthe water using a sieve and placed in the household trash. The rest isrinsed into the waste water.

Exemplary Embodiment 2 (Ceramic Special Paper-Ink-Jet Printer-IndustrialOven)

The second example describes an industrial application of theaforementioned principle. The further benefits of the method are usedhere. An investment must be made prior to use.

This time, a ceramic film in the green state is used as paper. It isessentially made of a silicate ceramic compound. This compound is mixedwith PVA and water and rolled out into a paper/film. A drying processthe

follows, in which all evaporable liquid is removed. The drying processmust take place below the glass transition point of the PVA and in agentle manner to avoid cracking. The temperatures must be kept below100° C. The paper may subsequently be plasticized between two heatedrollers, due to the action of heat, and calibrated for good parallelismand layer thickness control.

This paper may be further processed into sheets or used as a roll (600).After drying, it is elastically pliable, due to a thickness of less than100 μm, and may be bent into relatively narrow rolls having a radius of50 mm.

A device according to the invention for printing this roll provides foran unrolling unit, from which the material is fed to the process units.It is fed in a straight web under an ink-jet print head (602), anintermediate heating system and a calibration station (603).

In the example according to the invention, wax is used as the ink. Themelting point is set by adding a low-melt polymer (polyethylene PE).This material may be safely processed with the aid of an ink-jet printmodule at a temperature of 70° C. Ceramic particles may preferably beadded to the ink to reinforce the ceramic films.

The wax striking the paper is immediately cooled by the films andremains on the surface. A targeted local heating is therefore carriedout in a subsequent step. The wax penetrates the paper. A precisesetting of the speed of the web and the heating power are necessary tobind the paper roll afterward.

Another possible unit comprises diametrically opposed rollers. Theprojecting wax after the heating process, which is still flexible, iscalibrated to an exact projection over the film.

The web is then rolled up onto a roller (601) under a definedpretension. Ideally, the images should now be situated one on top of theother, so that the desired components would be accurate in terms ofgeometry and size with imaginary cuts through the roll.

Since inaccuracies in the system are to be anticipated, sensors are usedwhich continuously monitor the roll thickness. This signal is used toactively adjust the position and content of the printed images. Allnecessary conversions, such as conversion to polar coordinates, musttake place.

The printing process runs continuously. The speed is limited only by theink-jet print head and its design. All processing units may also bepresent multiple times. A true high-capacity production process is thusto be implemented by the invention.

At the end of the printing process, the roll is subjected to binding. Asin the process for the home user, an oven is used for this purpose. Thewax layers now melt into each other, and water-insoluble bodies form.The exact calibration and the high density of the rolled ceramic paperresults in a highly dense ceramic green body.

The removal in this case takes place in the same manner as described,using a water bath. Water changes, other temperature controls,filtration at the dissolving medium, mechanical cleaning by means ofhigh-pressure jets and automatic brushing may take place on anindustrial scale. The loose parts may be removed from the solution bysieving.

In this example using ceramic paper, a sintering step advantageouslytakes place after these processes. The wax is burned off in a firststep. This takes place at a temperature of up to 500° C. The molds areself-supporting, due to the high packing density even after thisso-called unbinding. The burning takes place at 1,200° C.

LIST OF REFERENCE NUMERALS

-   -   100 Special paper    -   101 Printed area    -   102 Paper stack    -   103 Heat    -   104 Component    -   200 Ink-jet print head    -   201 Ink droplet    -   202 Toner roller    -   203 Toner image    -   204 Printing needle    -   205 Ink ribbon    -   300 Heat source    -   301 Penetrated material    -   302 Spreading with material    -   303 Blow-off device    -   400 Unbound stack    -   401 Bound stack    -   402 Capillary action    -   403 Gravity action    -   404 Pressure action    -   500 Adhering paper    -   501 Water bath    -   502 Free paper remnant    -   503 Molten paper    -   504 Pulverized paper    -   600 Roll, including source material    -   601 Finished “stack”    -   602 Print unit    -   603 Heating and leveling unit

What is claimed is:
 1. A special paper, which is suitable for producinga three-dimensional body from individual layers, which includes thefollowing properties: a. a variable tendency to be dissolved by printingwith a medium; b. a capacity of the special papers to bind to each otherdue to an activation in the areas defined by printing; and c. asolubility of the unbound special paper due to the action of a suitablesolvent, heat and/or mechanical energy; wherein the special papercomprises: i. a water soluble polymer including polyvinyl alcohol; andii. a short cellulose fiber, a naturally occurring substance, a metal, astone, a mineral, or a ceramic.
 2. The special paper of claim 1, whereinthe special paper includes the cellulose fiber.
 3. The special paper ofclaim 2, wherein the special paper includes a fluid or a powder whichprovides the binding capacity to the special paper.
 4. The special paperof claim 1, wherein the activation of the binding capacity of thespecial paper takes place by a transferring of a fluid or a powder froman ink ribbon of a dot matrix printer, from an ink of an ink-jet printeror from a fixed powder of a laser printer or a laser copier.
 5. Thespecial paper of claim 1, wherein the solubility of the unbound specialpaper is due to the action of a solvent.
 6. The special paper of claim1, wherein the solubility of the unbound special paper is due to heat.7. The special paper of claim 1, wherein the solubility of the unboundspecial paper is due to mechanical energy.
 8. The special paper of claim1, wherein the special paper is flat and smooth and has a uniformthickness and/or the special paper is made of materials that may beglued together.
 9. A material system including a special paper, and aprintable medium capable of changing a binding capacity of the specialpaper in the printed locations; wherein the printable medium includespolyvinyl alcohol, polymethyl methacrylate, or a wax; and wherein thespecial paper is suitable for producing a three-dimensional body fromindividual layers, which includes the following properties: a. avariable tendency to be dissolved by printing with a medium; b. acapacity of the special papers to bind to each other due to anactivation in the areas defined by printing; and c. a solubility of theunbound special paper due to the action of a suitable solvent, heatand/or mechanical energy; wherein the special paper comprises: i. apolymer; and ii. a short cellulose fiber, a naturally occurringsubstance, a metal, a stone, a mineral, or a ceramic.
 10. The materialsystem of claim 9, wherein the printable medium changes the bindingcapacity due to microwave selectability of the printed paper.
 11. Thematerial system of claim 9, wherein the material system includes atemperature activatable substance and the binding capacity is due to adiffusion of the temperature-activatable substance.
 12. The materialsystem of claim 9, wherein the material system includes a bindermaterial that melts and the printable medium includes a material thatevaporates and prevents melting of the binder material that melts in theprinted regions.
 13. The material system of claim 10, wherein the bindermaterial that melts includes a material that has a high absorption ofmicrowave radiation having wavelength characteristic of a conventionalmicrowave oven that heats water.
 14. The material system of claim 9,wherein the binder material that melts is a plastic, and the printablematerial is free of humectant or other volatile constituents.
 15. Thematerial system of claim 9, wherein the printable medium includes waterand a component that prevents or reduces evaporation of the water,wherein the component that prevents or reduces evaporation includes asolid thickener or a liquid thickener.
 16. The material system of claim9, wherein the printable medium includes the polyvinyl alcohol or thepolymethyl methacrylate.
 17. The material system of claim 9, wherein thepolymer is water soluble.
 18. The material system of claim 17, whereinthe polymer includes polyvinyl alcohol.
 19. The special paper of claim1, wherein the special paper includes the cellulose fibers.
 20. Thespecial paper of claim 19, wherein the cellulose fibers have a lengththat is shorter than a thickness of the special paper.
 21. The specialpaper of claim 19, wherein the cellulose fibers have a length of 20 to30 μm and/or the special paper has a thickness of 80 μm.
 22. A specialpaper, which is suitable for producing a three-dimensional body fromindividual layers, which includes the following properties: a. avariable tendency to be dissolved by printing with a medium; b. acapacity of the special papers to bind to each other due to anactivation in the areas defined by printing; and c. a solubility of theunbound special paper due to the action of a suitable solvent, heatand/or mechanical energy; wherein the special paper includes: i. apolymer; and a ceramic.
 23. The special paper of claim 22, wherein thespecial paper is a green state film.
 24. The special paper of claim 23,wherein the special paper is dried for removing an evaporable liquid.25. The special paper of claim 24, wherein the special paper has athickness of less than 100 μm.
 26. The material system of claim 9,wherein the printable medium includes the wax.
 27. The material systemof claim 26, wherein the printable medium includes ceramic particles.